Nature “The White Lions” at 7 pm
This is the story of two remarkable and extremely rare white lion cubs on their journey to adulthood. Both are female, sisters born as white as snow in May 2009, in South Africa’s Kruger Park. Growing up on the savanna, they must not only overcome the same survival challenges that all young lion cubs must face, they must also overcome the threats their high visibility brings.

NOVA “Deadliest Tornadoes” at 8 pm
In April 2011, the worst tornado outbreak in decades left a trail of destruction across the U.S., killing more than 340 people. Why was there such an extreme outbreak? How do such outbreaks form? With modern warning systems why did so many die? Is our weather getting more extreme — and if so how bad will it get? This episode of NOVA looks at the science behind the April outbreak, meeting those affected and the scientists trying to predict tornadoes and understand whether this outbreak relates to global climate change.

NOVA “Hunt for the Supertwister” at 9 pm
A powerful tornado is a terrifying phenomenon that continues to defy decades of scientific efforts to predict it. During one of the worst tornado seasons on record, a NOVA camera team chased across the Midwest, capturing hair-raising footage of highly destructive twisters in action. But this is much more than just another “extreme weather” show, focusing on the efforts of two scientists at the University of Oklahoma to develop radically different approaches to forecasting twisters: one relies on “virtual tornados” created inside supercomputers, while the other involves hunting down real-life storms to collect data firsthand (the method that inspired the movie Twister). With jaw-dropping 3-D graphics generated by the National Center for Supercomputing Applications, “Hunt for the Supertwister” features spectacular footage of these terrifying twisters and gives viewers a front-row seat to the risky and thrilling art of storm chasing.